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Proceedings Paper

Dosimetry recommendations for NMIBC: a simulation and in vivo study (Conference Presentation)
Author(s): Lothar D. Lilge; Daniel Molehuis; Angelica Manalac; Fynn Schwiegelshohn; Vaughn Betz; Wayne Embree; Arkady Mandel; Roger Dumont-White; Girish Kulkani; Michael Jewett

Paper Abstract

Recurrent Non-Muscle Invasive Bladder Cancer (NMIBC) is a diffuse disease, and patients have failed standard BCG therapy face prophylactic cystectomy. PDT fell out of favour due to its variable outcome, and high morbidity. To overcome PDT associate toxicity to the bladder’s muscle layer, the use of shorter wavelength and instillation of the photosensitizer were suggested. While either approach was shown to improve the outcome in animal models they have not previously combined in human studies. Additionally, the effects of highly variable tissue optical properties of the bladder and its shape have not been studied. Here, we present surface dose histograms derived from light propagation simulation in 6 human bladders using CT images for anatomical detail and the FullMonte software package. The ability of a single light sensor versus 3 or 12 light sensors to measure the average irradiance on the bladder surface was evaluated as a function of the bladder wall’s tissue optical properties. Results show that the irradiance in non-spherical bladders can vary over an order of magnitude, but the irradiance histograms are affected little by displacement of the emitter inside the bladder void. As the surface area monitored by a single sensor depends strongly on the bladder shape, the responsivity of a single sensor to the average bladder irradiance can vary equally. Twelve light sensors monitor the entire bladder surface almost complete and hence their average responsivity is constant to the average irradiance on the bladder largely independent of shape. The dependency of the sensor’s response on the tissue optical properties is also lower.

Paper Details

Date Published: 14 August 2019
Proc. SPIE 11070, 17th International Photodynamic Association World Congress, 110704S (14 August 2019); doi: 10.1117/12.2526079
Show Author Affiliations
Lothar D. Lilge, Univ. Health Network (Canada)
Daniel Molehuis, Univ. of Toronto (Canada)
Angelica Manalac, McMaster Univ. (Canada)
Fynn Schwiegelshohn, Ruhr-Univ. Bochum (Germany)
Vaughn Betz, Univ. of Toronto (Canada)
Wayne Embree, Theralase Technologies, Inc. (Canada)
Arkady Mandel, Theralase Technologies, Inc. (Canada)
Roger Dumont-White, Theralase Technologies, Inc. (Canada)
Girish Kulkani, Univ. Health Network (Canada)
Michael Jewett, Univ. Health Network (Canada)

Published in SPIE Proceedings Vol. 11070:
17th International Photodynamic Association World Congress
Tayyaba Hasan, Editor(s)

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